Paraneoplastic syndromes such as dermatomyositis, often emerge as the initial clinical manifestation across various cancer types and are characterized by the development of B-cell responses targeting cancer-cell antigens that cross-react with normal skin and muscle cells. While these syndromes may alleviate following antineoplastic intervention, their response to immunotherapy remains elusive due to the exclusion of patients with autoimmune phenomena from clinical trials. In this report, we present the case of a female patient with advanced urothelial cancer presenting with dermatomyositis, who subsequently underwent treatment with anti-PD1 immunotherapy and experienced the onset of Stevens-Johnson syndrome. We discuss these two autoimmune entities and provide a comprehensive review of the existing literature to elucidate similar associations.
Keywords: Dermatomyositis; Stevens–Johnson syndrome; pembrolizumab; urothelial cancer.
Dermatomyositis, an inflammatory disorder that causes a skin rash, might be the first sign that someone has cancer. But when scientists test new cancer treatments, they often don't include people with this skin problem. So, we do not know much about how safe or effective these treatments are for them. Here’s a story about someone who had bladder cancer and dermatomyositis. They received a treatment called immunotherapy, but it caused a serious problem called Stevens-Johnson syndrome. We also found similar cases in medical papers.